A variety of storage racks of diverse constructions are known in the art, and generally such racks are constructed with specific goals in mind. In general, the provision of storage racks has the end goal of providing a maximum quantum of storage space utilizing a minimum of floor area. For this reason, it has been deemed advisable to construct and design storage racks which permit vertical stacking of one rack atop the other in order to maximize vertical storage of materials as opposed to spreading the storage of materials horizontally over a warehousing space.
Another feature of known storage racks relates to the particular materials which are to be stored. For example, some of the storage racks developed in the art are specific with respect to cylindrical loads whereas others are specifically designed for the vertical storage of flat sheet materials. For example, U.S. Pat. No. 3,844,600, issued in the name of the assignee of the present invention, is specifically directed to a storage rack which accommodates the storage of large cylindrical loads, while at the same time permitting the rack to be transported either by way of conventional fork lift trucks, or by way of lifting cranes and the like. Hence, it will be observed that the rack has specific features which permit not only the transport of the subject rack, but also features which accommodate the vertical stacking of racks one atop the other. Similarly, other racks have been designed with a view toward the convenient storing of larger flat sheet materials such as the rack depicted in application Ser. No. 418,859, entitled "Improved Unitized Modular Rack for Vertical Storage of Flat Sheet Materials," owned by the assignee of the present invention. The storage rack depicted therein is constructed in a manner to permit the modularization of the component parts of the rack such that a rack of a size sufficient to accommodate only those materials to be stored may be constructed on the situs of the warehouse facility. In short, by modularizing the component parts, the operator need not have empty storage bins on the floor to take up useable warehouse space when there are no materials to store.
Still other racks which have a variety of features convenient for not only storing materials, but also permitting the stacking of the racks one upon the other is shown in U.S. Pat. No. 3,565,018, also owned by the assignee of the present invention. The rack depicted in this patent is of the type permitting the easy storage of materials on a rack having a pair of opposed side walls and also including a series of four truncated feet which nest within nesting seats in order to permit the vertical stacking of the racks one atop the other. The advantageous feature of the rack depicted in the aforementioned patent is the fact that side walls are foldable into a flat orientation such as to permit the easy storage of the rack when not in use. A variety of other similarly hinged storage racks are known wherein the side walls or side and front and rear walls are all collapsible in order to permit the storage rack to be disassembled and stored within a minimum amount of storage space when not in use.
With respect to those racks having collapsible side walls or front and rear walls, or both, such racks have generally been found to be quite useful in that the same may be disassembled for ease of storage. However, where significant loads are to be stored within the rack and the racks then stacked vertically, the point of the hinged interconnection of the side walls or front and rear walls with the base generally presents a point of stress which cannot take heavy loads. Hence, while one obtains the feature of ease of disassembling and stacking of these racks within a minimum of storage space, one must give up the rigidity generally attributable to solid racks lacking any hinged members.
As to those racks which have been developed having rigid and non-hinged support posts or front and rear walls, generally these racks have been very difficult to store since they do not lend themselves to storage within a minimum amount of warehousing space.